<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>超链接测试</title>
<style>
  #nav a{
     width: 200px; 
     display: block;
     padding-left:20px;
     color:red;
     text-decoration:none;
  }
  #nav a:link{
     color:red; text-decoration:none;
  }
  #nav a:visited{
     color:#000;text-decoration:none;
  }
  #nav a:hover{
     color:blue;text-decoration:none;font-weight:bold;
  }
</style>

</head>

<body>

<div id="nav">
   <a href="#" onclick="style.color='red'" onmouseover="style.color='black'">aa</a>
   <a href="#" onclick="style.color='red'" onmouseover="style.color='black'">bb</a>
</div>

</body>
</html> 